4 files changed, 23 insertions, 2 deletions

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 9be335fb8a7c..0c8869fdd14e 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -172,7 +172,10 @@ static int load_misc_binary(struct linux_binprm *bprm)
                 goto _error;
         bprm->argc ++;
 
-        bprm->interp = iname;   /* for binfmt_script */
+        /* Update interp in case binfmt_script needs it. */
+        retval = bprm_change_interp(iname, bprm);
+        if (retval < 0)
+                goto _error;
 
         interp_file = open_exec (iname);
         retval = PTR_ERR (interp_file);
diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
index 1610a91637e5..5027a3e14922 100644
--- a/fs/binfmt_script.c
+++ b/fs/binfmt_script.c
@@ -80,7 +80,9 @@ static int load_script(struct linux_binprm *bprm)
         retval = copy_strings_kernel(1, &i_name, bprm);
         if (retval) return retval; 
         bprm->argc++;
-        bprm->interp = interp;
+        retval = bprm_change_interp(interp, bprm);
+        if (retval < 0)
+                return retval;
 
         /*
          * OK, now restart the process with the interpreter's dentry.
diff --git a/fs/exec.c b/fs/exec.c
index d8e1191cb112..237d5342786c 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1175,9 +1175,24 @@ void free_bprm(struct linux_binprm *bprm)
                 mutex_unlock(&current->signal->cred_guard_mutex);
                 abort_creds(bprm->cred);
         }
+        /* If a binfmt changed the interp, free it. */
+        if (bprm->interp != bprm->filename)
+                kfree(bprm->interp);
         kfree(bprm);
 }
 
+int bprm_change_interp(char *interp, struct linux_binprm *bprm)
+{
+        /* If a binfmt changed the interp, free it first. */
+        if (bprm->interp != bprm->filename)
+                kfree(bprm->interp);
+        bprm->interp = kstrdup(interp, GFP_KERNEL);
+        if (!bprm->interp)
+                return -ENOMEM;
+        return 0;
+}
+EXPORT_SYMBOL(bprm_change_interp);
+
 /*
  * install the new credentials for this executable
  */
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index a4c2b565c835..bdf3965f0a29 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -112,6 +112,7 @@ extern int setup_arg_pages(struct linux_binprm * bprm,
                            unsigned long stack_top,
                            int executable_stack);
 extern int bprm_mm_init(struct linux_binprm *bprm);
+extern int bprm_change_interp(char *interp, struct linux_binprm *bprm);
 extern int copy_strings_kernel(int argc, const char *const *argv,
                                struct linux_binprm *bprm);
 extern int prepare_bprm_creds(struct linux_binprm *bprm);